In-situ fabrication of martensitic stainless steel via heterogeneous double-wire arc-directed energy deposition

In recent years, there has been a growing focus on additive manufacturing of martensitic stainless steel with exceptional performance. This study introduces a new pathway to fabricate martensitic stainless steel through heterogeneous double-wire arc-directed energy deposition (DED). ER316L and ER70-G are used as raw materials, melting together and forming a common molten pool. A steel block with a chemical composition of Fe-11.38Cr-7.52Ni-1.44Mo-1.54Mn-0.497Si (wt.%) is successfully manufactured. The microstructure, mechanical properties and corrosion resistance of the martensitic stainless steel are investigated. The results indicate that the microstructure of the steel consists of martensite and austenite, achieving satisfactory microhardness (381.38 ± 11.94 HV), tensile strength (1172.1 ± 25.7 MPa), ductility (11.3 ± 1.3%), toughness (146.3 ± 8.0 J) and corrosion resistance (0.865 μA/cm²). This work demonstrates great potential of fabricating martensitic stainless steel using heterogeneous double-wire arc DED, providing a new choice to manufacture martensitic stainless steel and potentially other alloys.